Abstract
Mesenchymal stromal cells (MSCs) are widely used in clinical trials for the treatment of many bone defects. Apatite-wollastonite glass ceramic (A-W) is an osteoconductive biomaterial shown to be compatible with MSCs. This is the first study comparing the osteogenic potential of two MSC populations, heterogeneous plastic adherence MSCs (PA-MSCs) and CD271-enriched MSCs (CD271-MSCs), when cultured on A-W 3D scaffold. The paired MSC populations were assessed for their attachment, growth kinetics and ALP activity using confocal or scanning electron microscopy and the quantifications of DNA contents and p-nitrophenyl (pNP) production. While the PA-MSCs and CD271-MSCs had similar expansion and tri-lineage differentiation capacity during standard 2D culture, they showed different proliferation kinetics when seeded on the A-W scaffolds. PA-MSCs displayed a well-spread attachment with more elongated morphology compared to CD271-MSCs, signifying a different level of interaction between the cell populations and the scaffold surface. PA-MSCs also fully integrated into the scaffold surface and showed a stronger propensity for osteogenic differentiation on the A-W scaffold as indicated by higher ALP activity than CD271-MSCs. Furthermore, A-W scaffold seeded uncultured bone marrow mononuclear cells (BM-MNCs) demonstrated a higher proliferation rate and greater ALP activity compared to freshly isolated CD271-enriched BM-MNCs. Our findings suggest that enrichment of CD271-positive population is not beneficial for osteogenesis when the cells are seeded on A-W scaffold. Furthermore, unselected heterogeneous MSCs or BM-MNCs are more promising for A-W scaffold-based bone regeneration, providing novel insight with potential clinical implications in regenerative medicine for bone defects using an innovative tissue engineering approach.
